Gear tooth grinder having radially directed belt



Fb.18,19'58 s. s. EGARD, JR 2,823,494

GEAR TOOTH GRIND-ING HAVING RADIALLY DIRECTED BELT Filed sept. 19. 19552 'sheets-sheet 1 l I 'I Mill' Feb. 18, 1958 s; s. BOARD, JR' 2,823,494

' GEAR TooTH GRINDING HAVING RADIALLY DIRECTED BELT Filed sept. 1.9.19552 sheets-sheet 2l EAR TOOTH GRINDER HAVING RADIALLY nnzEcrED BELT SamuelS. Board, Jr., Snyder, N. Y., assignor to Farrel- Birmingham Company,Incorporated, Ansonia, Conn., a corporation of Connecticut Applicationseptember 19, 195s, seriaiNo. 535,078

9 claims. (ci. s114z) This invention relates to the grinding of gearsand more' particularly `to a device for grinding or finishing the teethof a gear blank by means of a traveling abrasive belt or other` membertraveling in a rectilinear path either covered with abrasive or havingabrasive, cutting or grinding members secured thereto.

In the past gear-grinding machines have generally ernployed rotarygearing wheels, which wheels rotate on their own axis and areadapted toengage the tooth of the gear to be ground. With machines of thischaracter theV toward and from the axis of the gear, the operative por#tion of the belt being so guided that it enters into the space betweenthe teeth so that it will grind over all or a large portion-of thelength of the face of the tooth at one time, and it is, therefore, onlynecessary to roll the gear relatively to the traveling belt to grind theentire face of the tooth. n

This rolling action is obtained in the present case by a combination ofa reciprocatingmovement imparted to the supporting mechanism for Vthetraveling belt soy that the belt is moved bodily in a reciprocating pathduring its traveling motion and a rotary movement of the gear blank.Moreover, as illustrated the rotary movement of the gear blank iseffected from the same source of power as the reciprocating movement ofthe belt support so that the twov motions are synchronized in order toeffect per-- face coverageV of the gear tooth by the grinding element.It is also contemplated to provide means for permitting the indexing ofthe gear blank so that one tooth after another may be presented to thegrinding element, in this case a belt. It will be understood that thefeature of actu? ating the grinding device so that it travels in arectilinear path, the belt being of a width to contact theentire lengthof the tooth face, is an important one in efiecting'a saving of time inthe operation of finishing gears and also in effecting a simpler andless complex mechanism than has been used heretofore as it eliminatesthe movement of a grinding device parallel to the axis of the gear blankv moves in and out of by a standard 28 which may be apart of thebase10,-

7 and the other end of this shaft is supported within the isv secured adiskfll havnarqcesseal irrita periphery..

ice

previously employed and one which will be capable of performing its workmore rapidly than prior devices of this character and which may beemployed with any type,

of gears such as spur gears, helical gears or the like.

Still another objectV of the invention is the provision of agear-grinding machine in which the grinding element is actuated over theface of the gear tooth in a rectilinear` path substantially transverseto, or toward and from, the axis'of the `gear blank, the grindingelement preferably being of a width to contact the entire length of thefacev of the gear tooth.

A still further object of the invention is to provide a gear-grindingmachineof the character describedwhereinthe grinding is performed by anendless traveling belt moving in and out of the space between twoadjacent gear teeth and held firmly, against the face of the tooth so asto perform its work effectively.

Still another object of the invention is to provide a gear-grindingmachine of the character described in which the supporting mechanism forthe grinding belt will be caused to reciprocate in timed relation withan oscillating movement of the gear'blank about its axis so that theentire curved surface-,of the gear tooth will be covered during thevgrinding operation.

To these and other ends the invention consists in the novel features'andcombinations of parts to be hereinafter described and claimed:

In the accompanying drawings:

Fig. l is a front elevational view of a gear-grinding machine embodyingmy invention;

Fig. 2 is a plan view thereof;

Fig. 3 is a vertical sectional view on line 3`3 of Fig. 2, some partsbeing shown in elevation;

Fig. 4 is a sectional View on line 4-4 of Fig. 3; and

Fig. 5 is a horizontal sectional view on line 5-5 of Fig. l.

To illustrate oneiembodiment of the invention, I have' shown in Fig. 1of the drawings a gear-grinding mechanism comprising base or frameportions 10 and 11, the portion 10, as will be hereinafter'described,serving as a support for the grinding mechanism, and the portionV 11serving as a support for the gear blank. A hollowvshaft 1,2 is rotatablymounted by suitable bearingsy within the supporting base portion 11,this shaft carrying at its upper end a table or support 13 upon whichthe is secured, as shown in dotted lines in Fig. 2.

Secured tothe lower end of the shaft 12 is a bevel gear 15, which gearmeshes with a bevel gear 16 carried by a sleeve 17. This sleeveisfrotatably mounted by suitable bearings 18 in the support 11, andsecured to a projectingbe effected hydraulically by means of a cylinder23 car-v ried by the support 10 and a piston rod 24 secured at 25 to theend of the carriage 22. It will, of course, be uu derstood that suitableconnections (not shown) are provided for introducing fluid presure intothe cylinder tov effect reciprocation of the carriage over a path of thelength desired depending on the dimensions-of the tooth to be ground.The carriage may, of course, bereciprocated by means other than thatshown without departing from the present invention.

As shownmore especially in Figs. 3 and 4, a shaft 26 is rotatablymounted at one end in bearings 27 carried sleeve 17 previouslydescribed. The shaft 26 projects outwardly from the sleeve 17, and uponits outerend Patented Feb. 18, 1958 gear blank 14 3 this diskcooperating with the indexingwheel 19- previously described.

A pi-n 32 is movably carried by a flange 33 of the indexing whe-el 19';the inner end ofthe pin being received in" vided if desired. With thepin 32 engaged with the diskV 30, it will be apparent that the worktable 13 will be actuated by the shaft 26 so that when this shaft isoscillated through the reciprocation of the carriage, as will b ehereinafter explained, the table 13 is also oscillated to move the gearblank or the gear tooth which is engaged with the grinding mechanism inan arcuate path which is coordinated with the reciprocation of thecarriage.

The oscillation of the shaft 26 from the reciprocation of the carriage22 is effected by means of flexible straps 36 and 37, one end of each ofthese straps being secured to the carriage as shown at 38 and 39 and theother ends being wrapped around a driving disk 40 and secured to theperiphery thereof, as shown at 41 and 42. The disk 40 is secured to theshaft 26, and with this construction it will be apparent that as thecarriage is reciprocated the disk 40 and shaft 26 will be oscillatedthereby effecting oscillation of' the work table 13 and the gear blank14 carried thereon.

A tool support 43 is mounted upon the carriage 22 for movementtransversely thereof so that the abrasive belt to be hereinafterdescribed may be fed into the work. To this end an adjusting screw 44may be mounted in the tool support 43 this screw being threadedlyengaged in a nut 45 (Fig. 4) secured to the upper surface of thecarriage. The screw carries a hand wheel 46 by which it may bemanipulated so that it may be adjusted transversely of the carriagetoward and from the work-supporting table 13.

. The tool support 43 comprises a `face member 47 of arcuate shape, asshown more especially in Fig. l, this member being braced in an uprightposition by the strut 48.

The member 47 is provided upon its face with a projecting rib 49 anddove-tailed slots 50 and 51 are provided at each edge of this ribbetween it and the face of the member 47.

Secured to the member 47 are tool carriers 53 and 54 which, as will behereinafter described, serve to support the grinding belts and alsooperating the driving means for these belts. Since these two mechanismsare identical, the description of one will sutlice for both.

As shown more especially in Figs. l, 2 and 3, each of these supportingmembers comprises a back plate 55 and a tool base 56. The back plate isprovided with dove-tailed grooves 57 and 58 (Fig. 3) which arecomplemental to the grooves 50 and 51 upon the member 47 so that thetool carriers 53 and 54 may be adjusted in an arcuate path relatively tothe member 47, thus adjusting the angle at which the grinding belt isdisposed, :as will be hereinafter explained, in order to grind gearshaving teeth of different helical angles. Any suitable means such assecuring members 60 may be `provided to hold the tool carriers 53 and 54in their adjusted positions.

At one face of the base 56 is mounted the motor 61, this motor having ashaft 62 which extends through the base and carries on its extended end-a drive pulley 36. Alsorotatably mounted upon the base 56 on the sameside as the pulley 63 are guide pulleys 64 `and 65, and anfadjustingscrew 66 may be provided lfor the pulley aerea-sae 4 64 in order toadjust the tension of the belt. Also supported upon the same side of thetool base 56 is a backing member 67 having a tapered nose portion 68adapted to project from the base 56 and extend between the teeth of agear to be ground,Y as shown in Figs. 2 and 5.

An endless belt 70 is trained around the pulleys 63,

64 and 6,5 and the backing member 68. As illustrated as shown in thedrawings, each of these being adapted to cooperate with-one. half ofthegear blank. Moreover, in the grinding of spur gears orV helical gears,either single or. double, the tool carriers 53 and 54 may beadjustedangularly or in an arcuate path with respect to the` member 47to change the angle of the plane of the belt with respect to the axis ofthe gear so as to adjust the belt for the tooth angle of the gear.

Invthe operation of the device the carriage may be drawn to one end ofits stroke so that the backing memb er `6,8 will clear the gear blank`so that the latter may be properly brought into position to be ground.By operation of the hand wheel the tool support 43 may bemovedfo'rwardly to set the belt in the proper position for the diameterof the blank and the tool carrier may be set at the proper angledemanded by the helical angle of the tooth of the gear.

The machine may then be started and, as the carriage reciprocates tomove the belt bodily back and forth while at the same time it isactuated in the direction of its Y lengthby the motorl 61 and pulley 63,the gear blank will be oscillated by means of the straps 36 and 37,shaft 26 and bevel gears 15 and 16.

:It will be understood that the width of the belt is preferably as greatas the length (width of gear) of the tooth to be ground, and thiscombined reciprocated motion of the carrier 53 or 54 and the oscillatingmovement of the blank 14 will result in the entire curved surface of thetooth being ground during this operation. The reciprocation of thegtablemay be continued as is necessary to finish the grinding operation.

After Vone tooth has been ground, the carriage may be moved to aposition at the end of its stroke, the pin 32 removed from the disk 30,thereby enabling the operator to rotate the indexing wheel 19 and bringa following tooth into position to be ground. This indexing may, ifdesired, be performed automatcally. It will be understood that theinvention may be employed in grinding beveled gears and -helical gearsas well as spurgears, and thefangular position of the-abrasive belt maybe lchanged for this `purpose so thatthe surface of the belt willliesubstantially parallel to the face of the tooth regardless of `itsangle; i

kIt will -be understood Ythat the particular shape and size-of vthebackinghmember-mhay be var ied to accommodate gears of diierentcharacter such as lgears having different 'diametral pitch or modifiedin other ways. This may Vbe readily effected by providinginterchangeable backing members so Vthat the proper one may beemployeddependng upon the characteristics of the gear blankbeingground.v

While I-have lshown and described a preferred embodiment of Vmyinventiomit will be understood that it is not to be limited to all ofthe details shown, but is capable of vmodification and variation withinthe spirit of the invention and within the scope of the ,claixilsw WhatIclairn is: Y 'i l. The method of grinding a gearblank which corn-Aprises moving au endless abrasive belt in the direction of its lengthalong a rectilinear path toward and from the axis of the blank and intoand out of the space between adjacent teeth on a gear blank, pressingthe belt against a face of one of said teeth, reciprocating the belt ina direction transverse to the direction of said movement, andoscillating the gear blank in synchronism with the reciprocaton of thebelt to cause the belt to make contact over the curved face of thetooth.

2. The method of grinding gears which comprises moving a exible belthaving abrasive elements thereon in the direction of its length over theface of a tooth on a gear blank in a path toward and from the axis ofthe blank to cause the belt to travel in and out of the space betweenadjacent teeth on the blank, and simultaneously rotating the gear on itsaxis and moving the belt in a direction transverse to the direction ofits travel to maintain its engagement with the moving gear tooth,pressing the belt against the face of the moving gear tooth, and

then indexing the blank with respect to the belt to engage the latterwith another tooth thereof.

3. A gear-grinding apparatus comprising a support for carrying -a gearblank, means rotatably mounting said support, a belt having abrasiveelements thereon, means for supporting and guiding said belt formovement against the face of a gear tooth on said blank in a rectilinearpath substantially transverse to the axis of the blank to cause saidbelt to move in and out of the space between two adjacent teeth, meanson said belt support for moving said belt in the direction of its lengthrelatively to its support, means for rotating the blank, means formoving the belt support in a direction to cause the belt to follow theface of the tooth during movement of the blank, and a backing memberprojecting outwardly from the supporting means and having a terminalnose portion extending into the space between two adjacent teeth on theblank, the belt being trained over the nose portion of said backingmember so as to move substantially directly toward and from the axis ofthe blank.

4. A gear-grinding apparatus comprising a support for carrying a gearblank, means rotatably mounting said table, a belt having abrasiveelements thereon, means for supporting said belt for movement againstthe face of a gear tooth on said blank in a rectilinear path in thedirection of its length substantially transverse to the axis of theblank to cause said belt to move in and out of the space between twoadjacent teeth, said supporting means including a backing member havinga nose portion projecting into said space about which member the belt isturned, means on said belt supporting means for moving said belt in saidpath, means for rotating the blank, means for moving the belt supportingmeans in a direction to cause the belt to follow the face of the toothduring movement of the blank, and means to index the gear blank withrespect to the belt to effect engagement of the latter with a succeedingtooth on the blank.

5. A gear-grinding machine comprising a table for sup`- porting a gearblank, means rotatably mounting said table, a belt having abrasiveelements thereon, means for supporting said belt for movement againstthe face of a gear tooth on said blank in a rectilinear path, and in adirection substantially radially of the blank, means on said support lormoving said belt in said path, means for moving the support in arectilinear path to move the belt bodily in a direction substantiallytangent to the blank, and means connecting said rotatable mounting meansfor the gear blank to the support to eiect rotation of the blank whenthe support is moved, said belt-supporting means including a backingmember projecting from the supporting means in a direction radially ofthe blank and having a nose portion projecting into the space betweenadjacent teeth on the blank about which said belt is turned to reverseits direction and move in and out of the space between two adjacentteeth on the blank.

6. A gear-grinding machine as in claim 5 wherein said belt-supportingmeans is mounted upon a reciprocating carriage for movement transverselyof the carriage toward and from the gear blank.

7. A gear-grinding apparatus as in claim 5 wherein means are providedfor adjusting said belt support to vary the angle'of the plane of thebelt with respect to the axis of the gear blank.

8. A gear-grinding apparatus as in claim 5 wherein the belt-supportingmeans is adjustably mounted on a reciprocating carriage, and means areprovided for adjusting said belt-supporting means to vary the angle ofthe plane of the belt relatively to the axis of the gear blank.

9. A gear-grinding apparatus comprising a table for supporting a gearblank, means rotatably mounting said table, a traveling belt havingabrasive elements thereon, a belt-supporting member, means thereon forsup porting the belt for movement against the face of a gear tooth onsaid blank in a rectilinear path substantially transverse to the axis ofthe blank, said means including a backing member having a nose portionprojecting from the supporting member into the space between twoadjacent teeth on the blank, said belt being trained about the nose ofsaid backing member to be reversed in direction within said space, meanson said support member for moving said belt along said path, and meansfor reciprocating said support and oscillating said blank in synchronismto elect travel of the belt over the curve of the tooth on the blank.

References Cited in the le of this patent UNITED STATES PATENTS

